Printing ink and method of using same



PRINTING INK AND METHOD OFUSING 1, SAME 1 William F. Talbot and Rolf Euchdahl, Englewood,"

N. 3., assignors to Sun Chemical Corporation, New York, N. Y., a corporation of Delaware v No Drawing. Application July 24, 1946, Serial No. 685,911

8 illainis. (Cl. 25083) l 2 This invention relates to methods for deterquired for that particular printing operation. As mining the amount of ink material required for a a result of the present invention, the printer is given number of printed impressions, or mileable to present to his customer an accurate estiage characteristics of ink materials'and also to mate of the amount of materials, including ink, ink materials suitable for such determinations. 5 required to complete satisfactorily a printing It is an object of the present invention to prooperation under consideration. vide a method for determining the amount of a In the present invention we include a subgiven ink or coating material which is required stance in printing ink which may be readily to produce a desired coverage upon a selected detected quantitatively in printed impressions. base material. This substance is distributed uniformly through Another object of the present invention is to the ink, in an amount which will not change the provide a method for determining the amount printing characteristics of the ink, and by of a given ink required to make a given number evaluating the amount of such substance in ink of printed impressions in a commercial printing applied to a unit area of printed surface, the operation, 1. e.,.the mileage characteristics of the '15 amount of such ink required to print any multiple ink. of such unit area may be determined accurately.

Another object of this invention is to provide This may be satisfactorily accomplished by maka method for evaluating the printability of ink ing a few test prints, and then by determining materials and of paper stocks under various comthe average amount of such substance present mercial printing conditions. in these test prints, the total amount of ink re- Another object of the present invention is to quired to print upon a desired area of surface of provide a treated ink material which is suitable any multiple of the same or substantially the for use in determining the amount of ink matesame printed area, or unit areas requiring subrial required to make printed impressions in a stantially the same amount of ink, of the same or particular printing operation. '25 comparable characteristics, may be determined Other objects of the invention will be apparent with adequate accuracy. The test prints should from the description and appended claims. be made upon the same or, a comparable kind of In the graphic arts industry, one of the imsurface as that which is to be used in the printportant requirements necessary to determine the ing operation under consideration, so that concost of a printing operation is a satisfactory ditions substantially comparable, in amount of method of estimating the amount of ink material i s p r unit a to' h Subsequent printwhich will be required in a particular printing ing operation will besecured.

job. And this is especially important with high Accurate and satisfactory results may be obspeed presses cfthe type which are employed to tained by dissolving or completely dispersing a print present day newspapers, publications and radioactive substance in a sample of the ink to the like. With such presses, the amount of ink be used in the actual printing operation. A mimaterial used per unit time of operation is relanute quantity of radioactive substance will be tively large. An estimate of the total amount lfil if ans d O Em thereof ink which will be required for the printing onsulting radioactivity, which means is sufficiently eration is necessary to prevent running out of ink .40 po v r t o e an a urate q a t w material before the printing operation isfinished, tive determination of the amount of radioactivity with consequent shutting down of the presses and in a unit printed area. successful practical r loss of time and money until additional ink is obsults have been secured by dissolving or disperstained, and to avoid the opposite danger of having a radioactive substance in a liquid which is ing a large surplus of ink material left over at the miscible with the liquid phase of the ink, and then end of a printing operation, the cost of which genadding this solution or dispersion to the ink :beerally must be addedto the printing operation, fore the grinding operation.

even though the ink is not employed for that The ink containing such dissolved or complete- J'ob. It is desirable that this estimate be ac- 1y dispersed radioactive substance then is utilized curately and readily performed, and that it in- 5 in a proof prlnting'operation of the kind norvolve a minimum of time and expense. mally effected in the ink and printing industry By the present invention we have provided to determine ink and paper performance, and methods of estimating with accuracy and presome test prints made on the paper stock or other cision, in advance of'a particular printing operabase to be imprinted." The prints are made in 'tion, the amount of ink material that will be resuch manner that they will have, as nearly as practicably possible, the correct film thickness for the best possible representation of the subject matter to be imprinted and likewise the correct film thickness to be secured in the final and more 7 lengthy printing operation. Predetermined areas of such test prints then are scanned to determine the amount of-radioaetivity present. From this amount, and the area of the printed surface which is scanned, the amount of ink which will cover any multiple of the unit printed area thus scanned with impressions requiring ink in amounts substantially comparable tosu'ch unit area can then be calculated-. I

To accomplish scanning of the printcd'material to obtain an accurate measurement of the radioactive substance present, an apparatus such as the Geiger-Miiller counter satisfactorily is employed. This apparatus is adapted so that it will give a count of the amount of activity of the radioactive substance. sists essentially of l ahigh vol tages source I which operates a specially designed; discharge. tube (called the counter) anamplifying and. electronic scaling circuit and a mechanical recorder. Highenergy electrons from the radioactive substance penetrate a thin mica window and produce a momentary discharge-in thecounter tube which is amplifiedand transmttted by the scaling circu-it tothe'mechanical recorder. f

Representative -of. an I ink material which satisiactorily can be utiJized a-ccording' to the pres- 'ent invention is'the following illustrative example: V

phenol formaldehyde-"resinfl 14.6 Diethyl'ene glycoLu, 55.9 Tracer material fa solution dispersion ofv aradioa'ctive substance-1' 3.1 Carbon black" 19.8

In practicaloperation, according to the present invention, aca-libratfoncurvje flrst'is set up to be utilized-in connectionwith-actual' testine operations. To obtain a-cal-i-bration curve, measurements are secured-bvmeansof the Geiger- Miillercounter-of the-background of cosmic radiation with the window of thecounter in position. This position of thewi r'rdow then is maintained constant throughout anyserie s of standardization and testing procedures, since the accuracy of the count of} radioactive-substance given by e such apparatusdepe'nds'upon thegeometry of the setup. A reading thendssecuredjfor the-radioactive substanceresent inf a known area of a standard printedl'surfa-ce, obtained by printing upon such'surfacevidthan'ink such as that de scribed in Exampielrwhere the Weight of the inkiilm on such areais -likewise*known.

The apparatus con- 7 For standardi'zf-ationprn'p'ose's, such weight d'etermination can be" made satisfactorily by a gravimetric method! A suitable gravimetrio method consists or in "rig a printing" plate, weighing the inked plat rn' aki'ng animpression, weighing the'plat'e-agair-i; and"- dete'rmining the ink used in pri ntirig-idi iferencer Inorder to give the required accuracy in weighing, the printing plate should consist eta-very thin sheet of copper held. firmly to-ahavy metal. base during the printing. operation. From'such readings a curve can. be drawn relating; the count ofradioactive substance-to weightof 'inls per unit area.

should preferably ha;

4 Such calibration curves, indicating the relationship above described, generally can be represented in the following manner:

Counts Per Unit Time Weight of Ink The point where the curve crosses the ordinate represents the background of cosmic radiation at the time and under the conditions of standardization and testing. The absorption of high-- energy electrons in the ink fiim itself is negligible for film thicknesses encountered in the. printing process so a straight line'can be drawn. through thetwci points'determined by, the background radiation and reading on the standard print. Because of the decay of the radioactive'substance the calibration curve changes with. time. it is necessary, therefore, to obtain a reading for the standard print at the time the testing operations are to be performed to'establisha calibration curve whichwili'b'ecorrect at'that tirne and for those conditions. It will be evident that theeradioactive substance decays at the same rate in the treated inkfmaterfa1' and inprintedimpressions made from the treatedi'nk' material. Hence the standard print. can' b'ej made with a known amount of thetreatedi'nk; as' described above, whenever convenient. prior to testingfoperations' with the same treatediink; and the radioactivity of the standard print'carr'then be measured to establish the calibration curve at the time the radioactivities of 'test impressions made with the same treated ink are. measured.

' Prints then can be madewith an. ink'sirch as that described 'in'EXample 1 upon various base stocks or under various printing. conditionssuch as will be encountered incoinmercial printing operations and counts made of the-amount of radioactivity of an area of the same dimensions as that utilized in obtaining the calibration curve. From the count" obtained, thefwei'ght of ink per unit area ofpaper is readily obtained of measurement orof "designation mayfbe employed. h V

The ink of Ex'a'mplefi is;ofthc type: adaptable for ,use in the-so cgall'edsteaincf water setting printing process whereinfthe*;settfng the imprinted ink issecured bytreatmentof-the'printed material with wa-teii for" eiia"niplei as steanr or vapor; 'A' solution oflra'dioactive tracenmatenm which has been eni-pioy'ed in this illustrative ink formulation is-a solutionfiof radioactive arsenic dissolvedas NI-EASOzi infwater; thdambdnt of arsenic H present being ofthe {order of 1'- mg. per m1. of water. However a rwaves large ber of radioactive substancesfare avaflable today at reasonable cost and other radioactive substances maybe-used radioactiv s-u-bstance a reasonable Tong 'Iralflifetime so that tests m with the same treated uncover? a? period 01 a raw weeks. The: radioactiveisubstatrceshould pref- .5 erablybe miscible or at least partially soluble in the liquid phase of the ink to obtain uniform distribution throughout the ink. The amount of radioactivity in the treated ink is not critical, as the Geiger-duller counter used to measure the amount of radioactivity is sensitive over an extremely wide range, and can be used to measure amounts of radioactivity ranging from minute quantities up to quantities far beyond the amounts ordinarily utilized in practicing this invention;

Another printing process is illustrated by the so-called heat-setting printing operation. In thisprinting operation a web of material is led through the printing press and is imprinted with an ink containing a binder material dissolved or dispersed in a solvent whose evaporation characteristics are such that no objectionable evaporation of the solvent occurs before the printing process, but upon heating of the imprinted web, solvent is removed therefrom by evaporation to leave a relatively non-offsetting and non-smudging print. Such printing process, and the inks therefor, are employed to a considerable extent in the preparation of present day magazines where speed in the preparation of the completed printed magazine is desired. Illustrative of an ink, useful in such process, and which can be utilized according to the present invention, is the To this is added, in accordance with the present invention, and to determine the mileage characteristics of the ink material, a radioactive phosphorus pentachloride dispersed in a mixture of Vehicles A and B in the proportions in which they are used in the ink material.

It is not necessary to know exactly the weight of the radioactive substance which is dispersed, since, as above describedjthe activity willbe determined in setting up a calibration curve and thisactivity related to the amount of ink per unit area of surface. Also, in subsequent testing operations, it is the radioactivit of the imprinted ink material which is determined.

The formulas of the vehicles utilized in the ink in Example 2 are:

Vehicle A Limed rosin 28.1 Rosin modified glycerol maleic anhydride These vehicles are prepared in the usual manner well known to those skilled in the industry, as for example by heating the mixture until all of the solid materials are dispersed or dissolved therein.

EXAMPLE 3 Red piginent 37.25 Bodiedlinseed varnish m 57.16 Cobalt. drier 2.79 Pastedrier r 2 .79

Forutilization, according to the present invention, there is added to this ink' a bodied linseed varnish containing radioactive phosphorus pentac'hloride. 4 l 7 There is provided, therefore, by the present invention, a method for determining mileage characteristics of ink materials which is simple in operation and by which determinations can be made withrelatively great speed and accuracy. There are also other ink and printing characteristics which can be evaluated by utilization of the methods herein described, for example, to determine the relationship between the amount'of ink on a. given printed area and the quality of the print. This relationship is useful'in evaluating the printability characteristics of inks and of paper under various commercial printing conditions. Determinations of this type have been made in which various amounts of the same ink were used to print on several' different paper stocks. The amount of ink was determined in accordance with this invention, the brightness was calculated from spectrophotometri'c-reflection curves, and. the print quality was judged subjectively from half-tone prints. The brightness of a black print of satisfactory print quality varied between 5.0% and 7.5%,'100% being the brightnessof a freshly smoked magnesium oxide surface. In the tests conducted a'good correlation was found between the print quality of the different paper stocks and the amount of ink required to obtain the same brightness rangeof 5.0% to 7.5% for each paper stock. Similar determinations can be used in evaluatiing the printability of different inks on a given paper stock.

While the methods and articles herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise methods and articles, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. The process which comprises incorporating a radioactive substance in a non-radioactive printing ink, in amount insufficient to change the printing characteristics of said ink, printing with such ink upon a surface, and subsequently degermining the radioactivity of the imprinted surace.

2. The process which comprises uniformly distributing, in amount insufiicient to change the printing characteristics of a printing ink, a, radioactive arsenic substance through a non-radioactive printing ink comprising a vehicle, which comprises a binder component immiscible in water, dissolved or dispersed in a solvent component miscible with water, printing with such ink upon a base surface, and subsequently determining the radioactivity of the imprinted base.

3. The process which comprises uniformly distrlbuting, in amount insufiicient to change the :heating 'of the imprinted Web, printing with such vehicle -upon a base surface; and subsequently determining "the radioactivity of the impfln'ted The process which comprises uniformly dis- .tribnting, in -:amQunt insufiic ent. to chang the minim? rharaciteristics swimmin -ml; ralad l aetive'v hosphorussub anceiniapnonerad oar t printing ink comprising a bodied iqigl -nih,, sprinting with 511 11 link 11mm ia. sur- {and subsequently .idete'rmining th radi ,aetivityzof'theimprinted:base. 1

5. l hep'method io'f determinin -mlleage :tharmctfiiistics. for coatin imaterials whiflljfinmfirises ihmorporating a :radioactive substance :in ya coatmaterial, in :amountdnsufiieient to salient Tthe .eoating characteristics ofsaidzmateriaLgapplying ssai'dzradioactivs coating :material Eto 8.511388 i-n idessired :fllm -'thickness, determining the ra-dimmstivity ::a known area xii-the treated ibase. rand ;-comparing:thexletermined radioactivltywith that 703 zazbase material :ofvthe same-or sin'riilar:nharaicteristies coated :with said :radioaetlve coatin gmaterial,.;and for whl1ch the radioactivity and wei h :Qr 'aaoatin 'per nit area have been :rle-

Tier-mined.

:16. 'EPhe. methodflof \aidetermimng mileage -.-char-- acteristrcs pf coating materials whichmompri'ses zincorrorating iradioactive arsenic tsubstanee tin :a -\enatin r-material,=in amount ,zinsuzflicient ctoeaafieet zthesz'oatm characteristics of :said imaiterial, said aogating fmateri'al comprising a water immiscible sbmder component iiissolvetl :or z 'disperse'zl in .a water :miscible solvent icomponent, applying zsaid ziazdiaaetive 'coatin'g material ato ;a Phase in :the alesi-relizfi'imsthickness, determining :the "radioac- .aomparing therrdetermirredradioactivity with-that of ithezhasezmaterlal of the-sameoresimllarkcharacteristicscoated with said radioactive coating .rnatcrial, iand '-'for which the radioactivity and weight fflf coating iper amit -;area have 'z'rbee'n ile-- 'termined.

' :7. {the gmethod of determining :milea'ge -charzacteri stiqs :Qf coating 'materials which comprises incorporating radioactive phosphorus substance in a coat n ma l. i ount s flfic nt t affect the ccatingcharacteristics of said .;materlal, said coatin trm te -i o p n a binder 10cmponentgiissqlved or dispersedin a .solvent corn.- ronent id s ve com nt h t- .1 s e a rationthara t r r s c hat is adesmatfi r vstable :at normal -;temperatures and evaporates vfromz-a coated film ppon application nf heat, sp-

plying said radioactive coating material to, base rinan'esiredifil thick essrd te m nin th r ad activi y or,-a:k wn area o t e cated baseand :comrarinsthe d te n d ad oact vity w th tha or .a base ma erial tithe sam o s m e acteristic's .coated with said radioactive coating material and :for which h r d oactivi y and ei ht 1.0: coatin rer n area ha hear ti 't.ermined.

'8. 713112 method of determining rIHilQflgG 'char, Facteristia: of coating materials which comprises incorporatingzaaraclioactlve substanq dn a cqating material, -ins-amount insuiflcient'to afiect the coat- 'irxg characteristics of said material, said-coating material comprising a drying -oi1 varnish, ,zapplyizrg said-radioactive coating material .to a base ,ln a desired film thickness, determining the ;;1:adi oactivity inf -:a known area of the c0ated'base,:and comparln'g'the determined.radioactivlty withthat of a base material of the same or similar-hilaracteristics coated :with :said radioactive coating material and for which the radioactivity and weight of coating per unit area have *been :de-

"-t ermined. V g

RQLF BUCHDAHL, LL AM 'EITALBQ REFERENCES CITED The following references are of record in the file of this patent:-

U NITED STATES PATENTS 

